Ways to wire Dual 4-Ohm Sub on 2 Channel Amp

I know already that I can wire it into a 2Ω Load, and thats only using one channel on the KX450.2 @ 225W. It's enough for the time being to power the subwoofer, because supposedly it's active @ around 75W. However, of course (if possible) I would like to get more power out of it and I do not have many options using a Dual 4Ω Sub on a 2 Channel amplifier.

Therefore my question being, are their any other configurations that might offer little more wattage using the KX450.2 amp please let me know?